When opening Vienna after upgrade to latest 10.13.4 beta, it crashes right away. At the same time, or just before, Avast Antivirus reacted with message “Infection blocked” with reference to file /Applications/Vienna.app/Contents/Frameworks/libswitchDispatch.dylib Avast had moved this file to the Chest, so of course Vienna could not start. I put the file back, and then Vienna started normally.

Edit: I have reported this to Avast as a false positive.

Edit 2: Received response from Avast. Thank you for reporting this.Our virus specialists have been working on this problem and it has now been fixed. If you're still getting the same detection, please make sure you're using the latest Virus Definitions in Avast.